Radars have generally used analog signal processing for a tracking loop to maintain output data of range, velocity and/or acceleration data for subsequent use. However, accuracy of such systems is limited due to, among other things, shifting of the frequency spectrum of the returned echo due to motion of the antenna or motion of the echo producing target with respect to the antenna. Attempts to improve the accuracy by digitizing the signals and utilizing digital processing accentuate these errors particularly if the processing converts signals from the time domain to the frequency domain, for example, in a fast fourier transformer since the errors now show up as shifts in the frequency components.